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 * Copyright (c) 2002, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */


package javax.management.remote;

import java.io.IOException;
import java.io.InvalidObjectException;
import java.io.ObjectInputStream;
import java.io.Serializable;
import java.security.Principal;

/**
 * <p>The identity of a remote client of the JMX Remote API.</p>
 *
 * <p>Principals such as this <code>JMXPrincipal</code>
 * may be associated with a particular <code>Subject</code>
 * to augment that <code>Subject</code> with an additional
 * identity.  Refer to the {@link javax.security.auth.Subject}
 * class for more information on how to achieve this.
 * Authorization decisions can then be based upon
 * the Principals associated with a <code>Subject</code>.
 *
 * @see java.security.Principal
 * @see javax.security.auth.Subject
 * @since 1.5
 */
public class JMXPrincipal implements Principal, Serializable {

  private static final long serialVersionUID = -4184480100214577411L;

  /**
   * @serial The JMX Remote API name for the identity represented by this <code>JMXPrincipal</code>
   * object.
   * @see #getName()
   */
  private String name;

  /**
   * <p>Creates a JMXPrincipal for a given identity.</p>
   *
   * @param name the JMX Remote API name for this identity.
   * @throws NullPointerException if the <code>name</code> is <code>null</code>.
   */
  public JMXPrincipal(String name) {
    validate(name);
    this.name = name;
  }

  /**
   * Returns the name of this principal.
   *
   * <p>
   *
   * @return the name of this <code>JMXPrincipal</code>.
   */
  public String getName() {
    return name;
  }

  /**
   * Returns a string representation of this <code>JMXPrincipal</code>.
   *
   * <p>
   *
   * @return a string representation of this <code>JMXPrincipal</code>.
   */
  public String toString() {
    return ("JMXPrincipal:  " + name);
  }

  /**
   * Compares the specified Object with this <code>JMXPrincipal</code>
   * for equality.  Returns true if the given object is also a
   * <code>JMXPrincipal</code> and the two JMXPrincipals
   * have the same name.
   *
   * <p>
   *
   * @param o Object to be compared for equality with this <code>JMXPrincipal</code>.
   * @return true if the specified Object is equal to this <code>JMXPrincipal</code>.
   */
  public boolean equals(Object o) {
    if (o == null) {
      return false;
    }

    if (this == o) {
      return true;
    }

    if (!(o instanceof JMXPrincipal)) {
      return false;
    }
    JMXPrincipal that = (JMXPrincipal) o;

    return (this.getName().equals(that.getName()));
  }

  /**
   * Returns a hash code for this <code>JMXPrincipal</code>.
   *
   * <p>
   *
   * @return a hash code for this <code>JMXPrincipal</code>.
   */
  public int hashCode() {
    return name.hashCode();
  }

  private void readObject(ObjectInputStream ois) throws IOException, ClassNotFoundException {
    ObjectInputStream.GetField gf = ois.readFields();
    String principalName = (String) gf.get("name", null);
    try {
      validate(principalName);
      this.name = principalName;
    } catch (NullPointerException e) {
      throw new InvalidObjectException(e.getMessage());
    }
  }

  private static void validate(String name) throws NullPointerException {
    if (name == null) {
      throw new NullPointerException("illegal null input");
    }
  }
}
